Cables of the metal-clad type typically comprise an outer metallic armor or sheath which may be insulated and a plurality of internal conductors or wires, some of which may be individually insulated. Such metal clad cables are used, for example, for conducting power and/or control signals to distribution centers, motors, panel boards and numerous other electrical and electro-mechanical apparatus.
The environments in which such cables may be used may vary substantially. That is, cables are often connected to another cable or an electrical apparatus in moist conditions, sometimes even in standing water, in sandy or extremely dusty conditions, in conditions where there may be surrounding potentially explosive gases and numerous other surrounding environmental influences. Such other influences include vibrations and cable strains introduced by mechanical actions such as by pushes and pulls. A cable connector used to connect the cable to another cable or an electrical apparatus therefor is also subjected to similar environmental conditions. Cable connectors that do not properly seal the cable in certain potentially hazardous conditions permit an additional potential hazard to exist. For example, such leakage can introduce adverse conditions to the sensitive components of engines, switches, controls and the like. Moreover, apparatus which is potentially hazardous itself, such as in the case of motors capable of exploding when they fail, should be completely shielded at the wall of the apparatus so as to prevent personnel injuries and injury to other apparatus in the event of such an explosion.
Various electrical codes such as the National Electrical Code (NEC) require connectors used in these situations to be "explosion proof", i.e., the connector must be capable of withstanding explosion within a box or enclosure to which it is connected, preventing ignition thereby of surrounding gases and thus preventing transmission of gases through the cable core.
Therefore, it may be seen that such cable connectors are desirably made to insure a tight fit around the cable to reduce the effects of cable strain, provide a grounded connection to the metal armor and seal the cable from the above-mentioned environmental hazards.
Explosion-proof connectors in present use generally include multiple components, and often from six to ten parts, including various gland nuts, bushings, pressure rings, sleeves, lock nuts, gaskets and the like. As can be readily appreciated, these various structures must include fittings wherein the parts must precisely fit together to perform their intended functions. The loss of any part, which parts are usually non-standard by nature, means that the entire connector may no longer be useful. Furthermore, a connector made of many parts that fit together in a specific order is not only time-consuming and sometimes difficult to assemble, but is often susceptible to being constructed in the wrong order, in which event the entire connector becomes ineffective. As the seals are not successfully assured, grounding connections are not effectively made, and the like.
Beyond the above-known connectors, the cable terminating art has seen improvement in explosion-proof connectors. In a commonly assigned, copending application, Ser. No. 06/369,112 filed Apr. 16, 1982, a cable connector is disclosed which provides an environmentally sealed connector with relatively few parts and which overcomes many of the problems of the prior connectors. Such a connector comprises a body, grounding sleeve for connection with the metal jacket and an extension of the grounding sleeve which receives a sealing compound therein. This compound, which is poured in the opening of the extension, surrounds the internal conductors, and when set, provides an environmental seal for the cable. A compression gland, which is secured by a gland nut to the body, encloses the jacketed end of the cable and provides a complete seal therearound.
While the above-mentioned connector provides the desired "explosion proof" seal, it is desirous to insure that the sealing compound poured through the extension flows through to the grounding sleeve to seal the cable by fully surrounding the armor and the outer jacket.